Two particles of masses m and 3m are moving toward each other along the x-axis with the same speed v. They undergo a head- on elastic collision and rebound along the x- axis. Determine the final speed of the heavier object.

Respuesta :

Answer:0

Explanation:

Given

two particles of mass m and 3m

They  move towards each other with velocity v

As the collision is Elastic therefore value of coefficient of restitution is 1

[tex]e=1[/tex]

[tex]e=\frac{Relative\ speed\ after\ collision}{Relative\ speed\ before\ collision}[/tex]

if [tex]u_1[/tex] and [tex]u_2[/tex] are velocity of approach of m and 3 m

and [tex]v_1[/tex] and [tex]v_2[/tex] are velocity after collision respectively

therefore

[tex]v_2-v-1=u_1-u_2[/tex]

[tex]v_2-v_1=v-(-v)[/tex]

[tex]v_2-v_1=2 v[/tex]

conserving momentum

[tex]m\cdot v+3m\cdot (-v)=3m\cdot (v_2)+m\cdot v_1[/tex]

[tex]-2mv=3mv_2+m(v_2-2v)[/tex]

[tex]4mv_2=0[/tex]

[tex]v_2=0[/tex]

Therefore velocity of heavier mass is zero

 

Answer:

Zero

Explanation:

m1 = m

m2 = 3m

u1 = v

u2 = - v

Let the final speed of m1 and m2 be v1 and v2 respectively.

Use conservation of momentum

m1 x u1 + 2 x u2 = m1 x v1 + m2 x v2

m x v - 3 m v = m v1 + 3m v2

- 2 mv = m (v1 + 3 v2)

v1 + 3 v2 = - 2v ... (1)

As the collision is perfectly elastic so the coefficient of restitution is 1.

Use Newton's formula

[tex]e = \frac{v_{2}-v_{1}}{u_{1}- u_{2}}[/tex]

v - (- v) = v2 - v1

v2 - v1 = 2 v     ... (2)

Add equation (1) and (2), we get

v2 = 0

v1 = - 2v

So, the heavier body comes into rest after collision.